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From:   Jinpu Wang <jinpu.wang@cloud.ionos.com>
Date:   Wed, 16 Sep 2020 08:02:20 +0200
Message-ID: <CAMGffE=rCcDxeQUk2GY+MHn+07Sn6S=Q6Gssu+RX_BB084uJsg@mail.gmail.com>
Subject: Re: [RFC] pcie hotplug doesn't work with kernel 4.19
To:     Lukas Wunner <lukas@wunner.de>
Cc:     linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
        linux-kernel@vger.kernel.org
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Hi Lukas,

see reply below
On Wed, Sep 16, 2020 at 7:48 AM Lukas Wunner <lukas@wunner.de> wrote:
>
> On Tue, Sep 15, 2020 at 04:15:15PM +0200, Jinpu Wang wrote:
> > We are testing PCIe nvme SSD hotplug, it works out of box with kernel 5.4.62,
> > dmesg during the hotplug:
> [...]
> > But with kernel 4.19.133, pcieport core doesn't print anything, is
> > there known problem with kernel 4.19 support for pcie hotplug, do we
> > need to backport some fixes from newer kernel to make it work?
>
> No known problem.  Please open a bug on bugzilla.kernel.org and attach
> full dmesg output for 5.4.62 and 4.19.133, as well as lspci -vv output.
> You may want to add the following to the kernel command line:
>
> ignore_loglevel log_bug_len=10M "dyndbg=file drivers/pci/* +p"
> pciehp.pciehp_debug=1
https://bugzilla.kernel.org/show_bug.cgi?id=209283
I added you as cc.
I will gather other logs as suggested, and upload them to bugzilla.
>
>
> > [  683.218554] pcieport 0000:16:00.0: pciehp: Slot(0-3): Card present
> > [  683.218555] pcieport 0000:16:00.0: pciehp: Slot(0-3): Link Up
> > [  683.271702] pcieport 0000:16:00.0: pciehp: Timeout on hotplug
> > command 0x17e1 (issued 73280 msec ago)
> > [  686.301874] pcieport 0000:16:00.0: pciehp: Timeout on hotplug
> > command 0x13e1 (issued 3030 msec ago)
> > [  686.361894] pcieport 0000:16:00.0: pciehp: Timeout on hotplug
> > command 0x13e1 (issued 3090 msec ago)
>
> Those timeouts look suspicious.  Perhaps the hotplug controller
> claims to support Command Completed Support, but in reality does not?
>
>
> > CONFIG_HOTPLUG_PCI=y
> > CONFIG_HOTPLUG_PCI_ACPI=y
> > CONFIG_HOTPLUG_PCI_ACPI_IBM=m
> > CONFIG_HOTPLUG_PCI_CPCI=y
> > CONFIG_HOTPLUG_PCI_CPCI_ZT5550=m
> > CONFIG_HOTPLUG_PCI_CPCI_GENERIC=m
> > CONFIG_HOTPLUG_PCI_SHPC=y
> > CONFIG_HOTPLUG_PCI_PCIE=y
>
> You may not need ACPI_IBM, CPCI, SHPC.
will consider this.
>
> Thanks,
>
> Lukas
Thanks!
Jinpu